The device described in this proposal addresses the need identified by the NINDS for high-density percutaneous feedthroughs and implantable electrical connectors for neural prosthesis. The goal of the proposed research is to develop a chronic system for the transcranial delivery of signals and power to and from high density, multichannel electrode arrays implanted in mammalian sensory and motor cortexes. The concept is for a system consisting of a hermetic multilayer ceramic package that can house VLSI circuitry such as multiplexers, amplifiers and telemetry. It can be mounted either on top of, or in the plane of, the skull and connects to the electrode array with either a ribbon cable or a multiwire bundle, the ceramic package will also provide a means of connecting to the external environment; initially the system will use an electrical socket, mounted on the package, that protrudes from the scalp. VLSI multiplexing and pre- amplification circuitry in the hermetic ceramic package will allow the use of simple cable connectors, even for large arrays. The technology to be developed will ultimately provide the basis for interconnect systems to be used in human experimentation with neuroprosthetic applications.